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Swordfish Physiology:  Heat conservation, vascular specialization and muscle function. (NSF award # IOS-1354772)

Collaborative researchers:
Diego Bernal, Ph.D. (University of Mass., Dartmouth)
Ashley Stoer, doctoral candidate (UMD)
Jeanine Sepulveda, PhD (MiraCosta College)
Doug Syme, PhD (University of Calgary)

PIER researchers are collaboratively working with several laboratories to investigate several aspects of swordfish physiology.  Given the PIER teams access to live swordfish, ongoing studies range from examining heat balance and vascular specialization to the effects of temperature on muscle performance.

Thermal Studies
This work uses a suite of laboratory and field techniques to better understand how the swordfish is capable of expanding its thermal niche to waters well below the thermocline.  The thermal studies use modified PSATs to log the internal body temperature of free swimming swordfish.  The transmitter package has a thermistor that records body temperature at the location of the tag anchor.  Once the tag releases from the swordfish, the PIER team sets out to recover the transmitter package.  Muscle heating and cooling rates are examined over the course of the track period to assess the degree to which swordfish elevate internal muscle temperatures.  


Vascular Specialization

Vascular tissue from the central and lateral circulation are fixed, stained and sectioned for examination using light microscopy.  Additional work includes the tracing of the circulation to and from the red muscle to better understand blood flow pathways in swordfish.

 Muscle Function

This work brings together a collaborative team of researchers to investigate the effects of temperature on the contractile kinetics of swordfish muscle using the work-loop technique.  Muscle preparations from freshly caught swordfish are isolated and transported live to the PIER laboratory.  Once in the lab, the muscle preparations are cut down in size and mounted to a force transducer in a temperature controlled rig (shown to the right).  The live muscle bundle  is then subjected to work loop experiments over a series of temperatures (4-24oC).  This work assesses how swordfish muscle performs over a range of operating temperatures and forms the basis for doctoral student Ashley Stoer's dissertation in the Bernal Laboratory at the University of Massachusetts, Dartmouth.  

More About P.I.E.R.  
The Pfleger Institute of Environmental Research, PIER, is a non-profit 501(c)(3) organization based in Oceanside, California.